Forming continuous sheet glass



. Patented Mey 4, 1926. y

UNITED STATES PATENT oFFicE.-

ENOCH T. FER-HOREN, OE TOLEDO, rOHIO, ASSIGNOB I'l'.O THE LIlBIBEY-ONENS SHEET GLASS COMPANY, OF TOLEDO, OHIO, Al CORPORATION OF OHIO.

romaine coNTmUoUs snnE'iiGLass.

application inea February as, 1924. semi No. 694,930.

To all whomI t may comer/n.7 l I Be it known that I, ENocii T. FERNGiiEn, :i citizen ot'Sweden, residing at Toledo, in the county of, Lucas and State of Ohio, have invented new and useful Improvements in Forming Continuous Sheet Glass, of which the following is a specification.

This invention relates to improvements i in the art of producing sheet glass and more particularly to an improved process and appaiatus for fiowing glass downwardly oyer aplurality of directing and supporting members from which the molten glass is drawn away yin sheet form.

In drawing a sheet of glass downwardly from a supplying lHow, which is retarded in its vertical descent bythe walls of the slotted orilice, or by the walls of a clay slab around which the supplying How in spread, streaksor striations are apt to develop in the glass sheet, as well as a multitude of fine lines running in the direction in 4which the sheet is drawn. The clay parts over which the glass is drawn will gradually dissolve and crumble under the chemical action and the `drawing, strain, and the material pulled away from these parts .will be drawn into the sheet. y

When drawing through aslotted orifice, the lglass clinging to the clay walls picks up alloy and.v additional silica which tends to produce an exceedinglytough glass adjacent to the clay wall ,of the orilice, whichV glass willvbe pulled downwardly along the side walls of the orifice and cause striations in the surface layer of the sheet. Whenthe' sheet is drawn from a supplying fiow which descends alongtlie exterior of n clay'siab,

the same' phenomena will 'develop but not to such a marked degree, since thev stress lines within the glass formed by thepull on communicated to .the surface glass of the sheet. It may be Seen in both instances vcited that the injury done to the glass sheet is caused by Vtransmissionot1 drawing .force l' totliat glass whichv more intimatelyy as, sociated with or 'clings to tlieclay members 4 over which the glasspasses.l

' molten glass flowsfjfroni @container onto and successively around a series of directing per member reunites-into a single stream which is delivered to the upper surface ot the lower member. This lowerinember is pi'eferabl formed of a suitable metal, such as an val oy of nickel or tungsten, which when coverd by the glass stream, will be practically indestructible, and from'the surface, of which the sheet supplying stream will not absorb, dissolve, or carry ott any noticeable amount ot oxide or metallic ma@ terial, and along the surface of which there -will be'less adhesion of the glass stream.

The molten glass liowsas in the lirst instancearound b'oth sides of this lower vdirecting member, the twon streams uniting at the lower edge of the member and liowing or being drawn' downwardly therefrom in sheet form.

port the two directing members in adjustablefrelationv with respect to cach other and :to the source of molten glass, and the directingmiembers are souirounded by suitable means rforregulating the temperature of the' glass as.' it passes downwardly thcrearound 'prior to the formation of the sheet.'

The invention will be more clearly understood from the following detailed descrip tion of certain forms of apparatus involving the principles of this invention.

In the accompanying drawingsz-.

Fig.' .lis Va. 'perspective view, parts `being 'broken away, and the forward portionlot the apparatus beingv shown in longitudinal vertical section.

Fig. Q-Yi's an elevation ol one end of the directing members andthe adjustingand supportingv means therefor,

Means are provided to individually sup- Fig. 3 .is an elevation of the adjusting,

mechanism looking from the left at g.2.

Fig. 4 is a vertical section through .a modifiedformof'the apparatus.' l

LA body oi niolten glassindicated atll is f`niai ntainedin theextension'2 ofgatank-,or 'According to thel present invention, vthe other receptacle,and the glass level will be suchv that the glass tends to constantly overplastic condition of the owing stream 4 -ilow the lip 8 at the iront end of the receptacle in the form of a thin stream 4. The depth or volume of this overflow stream 4 may be regulated as desired by any suitable gate or valve, preferably located back of the extension 2 of the tank, andonot here shown. At is indicated a vertically adjustable cooler, or hollow shield, through which a supply oi air or other cooling liuid may be passed. By moving this cooled shield closer to or further from the surface ot' the molten glass 1, the temperature and may be regulated.

The transverse slab or directing member (i is adjustably positioned in front of and slie'htl 1 below the overflow li 3 as indi e l P a cated in the drawings, so that-the stream 4 passing over this lip will be caught upon the rounded upper surface 7 of this slab. This member may be made of clay or other refractory material, or may be formed of a metallic alloy like the lower member. to be described hereinafter'.

At each end of the member 6, a supporting bar 8 passes out throughan opening in thel side Wall 9 of the enclosing structure, and is supported in a bearing 10 laterally adjustable in a supporting'bracket by means of set-screws 12 and 13 at the two sides thereof. The bracket 11 is slidable vertically between guides 14, and is supported by the screw-bolt 15 assing through the fixed eye 16 and havmg adjusting nut 17 on the upper portion thereof. By suitably manipulatin the adjusting means just described, the irecting member 6 may be'raised or lowered, and moved toward or from the lip 3. In this Way the molten glass 4 whic is received upon the upper portion 7 of the directin ,member may be distributed als desired etween the front and back faces of the member down which it flows in the formv ol thin streams 18 and 19, which flow down the inwardly tapering lower sides of the member to unit at the lower edge 2O in the form of a single thick stream 21.

This directing member 6 acts as a. su porting and distributing member for t e downwardly flowing glass' and functions to deliver a wide even stream of molten glass to the upper receiving edge of the lower or some similar material;

directing member 22. This short downwardly Howing stream of glass 21 between the two directing members has both faces exposed to the heated gases within the enclosing chamber, thus facilitating the temperature control ofthe ylass delivered to the lower directing mem er 22.

The main lower directing member 22 will be formed of a suitable heat-resisting metal, preferablyan alloy of nickel and tungsten, 'I'his'metallic member will normally be completely"'ur rounded by the molten glass, so thlttthere weasel is no appreciable exposure to the atmosphere, and there will be practically no oxidation or chemical destruction of the metallic surfaces. Preferably, this member is made hollow as at 23 `to reduce the weight, and it -found necessary heating means may be employed within this space-23,'

The stream of molten glass 2'1 is received uponr the upper edge 24 of member 22,

which splits the streazn into two thin streams 25 which flow down the rather long, gradually diverging side faces 26 of the member. These faces 26 extend down to the outer corners or ledges 237, from which the side walls slope rather sharply inward as at 28 until thev meet at the lower edge`29 of the slab; The molten streams-'125 will adhere to and flow slowly down the rather large supporting areas'o faces 26, but after rounding the ledges 2T will be drawn. down more rapidly along the lower convergii'ig` .be fixed in any adjusted position bythe sete screw 35. Bracket 33 is slidable vertically along a guide rod 36 and `is held inadjusted position thereon by thevnut 3'? which screws upon a threaded1 portion 380i the rod.- lRod 36 is pivotally hung at its upper end on pin 39, and its lower end-40 maybe swung te the desired adjusted position by means of screw 41. By means of the adjusting apparatus just described, member 22 may be` raised o1" lowered, movedv laterally, 'or invclined to the vertical as desired. Intliis way it may be properly positioned belowthe upper member 6 which feeds the molten lass thereto, so that the streams 25 flowing own the two faces of the member will have. an 'i equal volume and velocity.-

The two directing members are completely enclosed within' a chamber which is heated by any suitable arrangement of burners s/uch as indicated at 42 and 43. Preferablythe lower slab .22 is protected from the direct action of the heaters. by the vertically adjustable side slabs or partitions 44 and 45,

which will radiate an even moderated heat y upon the glass sheet.

flowing glass streams', which pass down the lower sides 28 otmember22 to uniteat lower edge 2 9and be drawn away in sheetv form, are normally given more or less plasticity by the amount of cooling atmosphere which is permitted to pass Aup through slot.

structure, adjacent vthe sides of sheetv 550` the widthv of the exit slet 46 serve to var and to there y regulate the amount of; heat retained in this lower portion of the chamel. f.' y In the modification shown in Fig. 4, the uppermost directing member is in the 'form of a cylindrical roller 48. It desired this roller may be rotated, preferably 'in the direction of the arrow as shown. This rotation of the roller will assist the inner stream of glass 49 in its movement between the roller andl the adjacent face of overflow li 3. As shown in Fig. 4, lip 3 is formed with a metallic edge-plate 50 at the point where the flow 49 leaves the li to avoid the at this edge and consequent injurious e ects `Either form of upperv as described, will daliver the Amolten glass to the lower member in an even vertical stream. The upper 'member also' acts partial support for this stream, thereby de-V creasing the velocity of'low with which itis delivered to the upper edge 24 of the lower directing member. The molten glass streams'do not have as great adhesion withthey smooth surfaces of the lower metallic member, lbut the comparatively long diverging upper' faces of this member` oder an increased clinging area which oiisetsl the weaker adhesive properties. As stated above, there will be practically no physical wear or chemical deterioration of the metallic supporting member, and consequently no injurious e'ects Will be imparted to the glass streams iowing thereover.

The amalgamation with or the adsorption by the surface glass ot rthe streams, otatomic matter from thecombusting atmosphere'ot the heating space and the slight surface cooling of the glass streams 28 flowing down the convering lower surfaces of member 22 below the' ledges 27, will form a sdpericial skin of greaterinherent cohesiveness on these streams, which assumes the greater part of directing member the drawing stress. This tractive force opl erating through the ldrawn glass converging below the ledges27 is communifcatedfto each surfaceof the streams 25 on the upwardly taperingportion. of member 22. This pull on the superficialv layer of the surface glass tends to draw it in advance of the remainder oil the flow and at a greater speed toward the' outermostledgcs2 y As these exterior superficial surface films of glass'come under drawing stress and at tain a progressive acceleration in the line of draw, before the main body of the slower flowing layer of glass received such impulse, these iilms are caused to move downward at amuch faster ratev than the rest of the glass, progressivelv accelerating the advance of the adjacent glass or that surface glass which is subadjacent to the more cohesive superiicial surface, so that at the wider reach ofthe spread 'flow a certain proportion thereof falso becomes considerably accelerated and moves along with the surface layers-as they are bending inward toward one another around the laterally projecting j side promontories'or ledges '27 on the ineinber 22. 1

The drawing force thus operating on the flared-out portion of the forkedr flow will 1speed the downward movement-ot' only a.

relatively small portion of the flow because ofthe somewhat dynamic concentrioprcssure exerted byy the more cohesively knitted and tensioned surface films against the destructive crumbling away o `the clay art more vfluid glass of the enflding or forked inward'and` u wardly of. the upward tapering portion ol) the member 22, and thereby exerts a sort of an upward squeezing eli'ect on the body of the flow and also magnities the support given to this glass by each slantingside of the upward taper of the member 22, which altogether in practicaleii'ect will enhance the internal vsupport given, and balance the action of gravity o'n a portion of the glass moving down along each side ot' the upward taper of the member 22.

In the glass How thus accelerated and rc tarded, there' will be no occasion for the drawing stress to reach through 'the flow'tothe member 6 and thereby drag on the iiiterior surface glass clinging to the faces of this member, and while the flow divided during its descent by the wedge member 22 comes under the iniluence'oifb the tractive force while traversing the wedge, andis `accelerated; the real. attenuating stressanti stretching action, where the glas's'movenient i Ril.

there is a swifter progressive increase in speed resulting in an immediate sheet ioriiiation in which there may thereafter be but very little further stretching if proper support is given tothe drawn sheet.

The sheet ot' glass may be formed beneath the member 22 withoutany material Iresistance liioin the surface of the lower taper 28 of the member if the two ,glass streams flowing from the ledges 27 to the point 2 9 are maintained in relatively freely lowing state and the streams at the same time are kept relatively thin by being reduced in quantity.

The single streams of glass thus forming at the 4edge point 29 and departing therelroiii, will hang as a suspended sheet area through the slot 4G, the weightvof the Asheet f area formed acting to stretch the stream tov proper sheet thickness.

W'hen the sheet is formed in this manner no drawingforce is required, the requirement in this instance being that the sheer be' supported and taken awa)7 as it is formed. 'lhe glass sheet formed in this'ivay will become plastically stable as it emerges through the slot 4G and should preferably be turned and carried horizontallyv through the leer where it is gradually cooled 'and then d'"elivered to the lcutting table.

In order to maintain the glass streams in a high] y fluent state as they form the single stream at point 29, the tiles 47 should be aboutlas shown in Fig. l, land the tiles 44 and 45 elevated to a higher position.

Claims:

l. The process of producing sheet glass,

v.consisting in producing a plurality of streams ot' molten glass, uniting the streams to produce a single stream, then dividing the stream into a plurality of streams, after phlch they may again be united into sheet orm.

2. In the art of making sheet glass,itliat step in the 'formation of acontinuous sheet of glass which consists in `advancing the glass which is to compose the sheetin stream i `formation alternately in plural and in .l as it traverses and departs from that clinging surface, which is positioned at the lowest point in its vertical path.

4.; VThe methpd of producinga continuous sheet of glass which consists in flowing a shallow stream of glass downwardly from a supply, in cascading the glass of said stream over the opposite sides of guiding members positioned in the same vertical plane and spaced from one another, and in forming the sheet by accelerating the advance of the glass o' thestream as it arrives at the lower end of the lower guiding member.

- 5. The method of producing a continuous sheet of glass which consists in flowing 'a shallow stream of glass downwardly from a supply, in cascading the glass of said stream over the opposite sides of guiding members positioned in the same Vertical plane and spaced from one another, and in forming the sheet by .causing constant stretching force to operate on the glass of the stream as it arrives at the lower end of thelower guiding member and during said progres-' sion of the glass stream heating the opposite sides thereof.

(5. The process of producing sheet glass, consisting in producing a plurality ol streanis ot molten glass, thenpassing the streams over `the`opposite sides of spaced guide members, one stream .on each side thereof, and then uniting the streams into `sheet form.

7 The method of drawing a sheet of glass which consists in advancing the glass from which the sheet is drawn, through a heated space inffilmflows over the opposite sides of a vllow guiding member, in uniting the Vsaid iilms into a single depending flow formation beneath said member, in spreading .the glass of said formation over the opposite sides of a flow supporting member and advancing it downwardly tliereover toward a point otl eonliuenee thei'ebeneatli as separated iilm flows and forming the sheet by applying drawing force to the said liows at their point of confluence, while reducing their surface temperature.

8. In the art -of making sheet glass` the method of handling the glass before foriningthe sheet which consists indelivering the glass originally asa relatively wide and shallow flow toward and 'over the exterior of a horizontally positioned member in a manner to divide the glafss into two shallower flows proceeding dewnwardly on said .ineinber,-in ing said. flows into a'single flow beneath said member, and thereafter in again dividing and euniting the said single flow in a similar fashion prior te'jhe. application of drawing force thereto. Vf

9. In the art ol' .making sheet glassfthe method of handling the glass before forining the sheet which consists in delivering the glass originally as a relatively wide and shallow flow toward and over 'the exterior of a horizontally A'positioned member in a manner to dividethe glassinto two shallowei` flows `proceeding downwardly on said I lill) member, in unitingsaid ows beneath said member, in again dividing andreuniting the liowingA glass in a similar fashionprioi` to the application ofl drawing force thereto, and in exposing thevopposite surface areas of said 4flow to the influence of heat while in transit to tliepoint of-shcet formation.

10. In the art of makingsheet glass, the method of handling and treating the glass which consistsin delivering the same as a relatively shallow tlow of wide extent from a supply over the exterior ot two horizontally extending flow supportiner members which are positioned one above the otherin amanner to first divide and thereafter reunite the How in succession at and below each member, and in producing the sheet by tractive acceleration of the How movement at the lower end of the lower flow supporting member.`I

11. The method of producing sheet glass which'consists in advancing the glass supply for the sheet as relatively thin film flows over the exterior surfaces of separately spaced guiding members which are positioned one below the other, in uniting the said flows in the space between the lsaid members and at the lower point of the lower member, in heating the 4flowing films in a manner to maintain their fluid mobility toward the 'lower point ot the lower member, and in causingia loss of heat from the ex vterior of the films uniting at the lower end of said member while applying drawing force to accelerate the movement ot the films as they unite to form a sheet area beneath said member.

12. The step in lthe process of producing lsheet glass, consisting in producing a pluralit;7 of streams of glass, then passing, the streams over the opposite sides of spaced guide members, one stream on each side thereof, the streams uniting between the guide members.

13. In the artvof making sheet glass, the method which consists in delivering molten glass over the exterior of a horizontally! extended member, in a manner to 'first divide the'glass into two separated Hows and thereafter reunite the same into a single flow bcneatinsaid member, and in again dividing and .reuniting said How at a predetermined point beneath the said member with another horizontally extending member, and fouling the sheet area b v flowing the glass in a thin film from the lower member and by,y con-- stantly removing said tilm as it ishbeingA formed.

'14.'In the art of making sheet glass, the i method which consists in advancing a shallow ilow of. molten glass from a supply, in intercepting said iiow at a, predetermined point in its path of advance and causing the same' to become ldivided and thereafter united and in again intrcepting, dividing,

and reuniting said flow while communicating drawingv forceto the 4divided Hows as they are reuniting.

15.. In the art of making sheet glass, the process which consists in causing a shallow overflow of lass from va supply towards point ot' vertical descent, inintercepting the glass at said point with a rigid member in a manner tolirst form adivided and thereafter a reuniting stream'iiow during the early descent of the glass, in intercepting the descending stream beneath said member with a rigid metallic part having upwardly and downwardly converging side areas `to thereby divide and ieunite rthe iiow a second time, and forming the sheet by drawing;

glass ot predetermined thickness from. theeol guide members and separating over the next lower guide member. p

17. The process of producing sheet glass, consisting in producing a plurality of streams ot glass, then passing the streams over tbe opposite sides ot spaced guide members, one stream on each-side thereof,` the streams .flowing down the sides of the guide. members and uniting at the bottom 0f each of said members.

1S. The process of producing sheet glass. consisting in producing a' plurality of streams of glass, thenl passingthe streams over the opposite sides of spaced guide members. one stream on each side thereof, the streams flowing down the sides of the' guide members and uniting at the bottom of each oi said members, the streams being removed from the last guide member in united sheet form. y

19. In the art of making sheet glass, the method of forming a sheet, "which consists in delivering a shallow and lwide flow of molten glass from a supply over the exterior of a horizontal rigidl member in a manner to first divide the flow and thereafterreimite the same, and in again dividing and rep uniting said low at a`predetermined point beneath said member prior to the drawing los j 'of the sheet' with a rigid part shaped to predelivering a wide flowof molten glass from a supply `over the e'xterior of a rigid member in a manner to irstdivide the flow and thereafter reunite the same below said member, and. in again dividing and: reuntng the How at a predetermined point beneath said member by introducing a horizontally extending metallic part in the path of descent of the previously united glass How, prior to the application of drawing force thereto.

2l. In the art of making sheet glass, the step in forming a sheet which consists in delivering a wide iiow of molten glass from a supply over the exterior of a horizontally mounted rigid member in a ymanner to first divide therflow and thereafter reunite the same and in causing a second division and reuniting of said flow at a point beneath said member by introducing in its path a horizontally extending metallic part having a downwardly pointing wedge-shaped body.

22. In the art of making arcontinuous sheet ofglass, the step in forming the sheet which consists in delivering a shallow and wide flow of molten glass over the exterior of a horizontally extending member in a manner to first divide the flow and thereafter reunite the same, and in again dividing .and reuniting said fiow at a predetermined point beneath said member by introducing a horizontally extending metallic part having an upwardly and downwardly tapering body formation along its entire horizontal extent inthe path -of descent of the glass How prior to the application of drawing force thereto.

23. The method of forming a sheet of glass, which consists in delivering the glass which is to form the sheet along two separate paths coniiuently toward a common path of advance as a single stream, ingiving internal support'to the stream a suitable distance beneath its y point of formation while again dividing the same into separately flowing layers, and in causing said layers to reunite and form a descending sheet area.

24. The method. of treating a flow of glass and drawing a sheet therefrom, which consists in advancingmolten glass downwardly from a furnace chamber as a wide and shallow stream, in cascading the stream during its descent over the opposite sides of horizontally extending flow impeding members which are positioned in the same vertical plane, one below the other,'in progressively reduoinggthe temperature of the superficial surface of the cascading flow towards its lower point, and in accelerating its move- -nfient of departure from the lower member by the application of drawing force, to thereby produce a drawn sheet area beneath said member.

f'Q. In the making of sheet glass, the method which consists in causing molten glass to descend along the opposite sides of a horiaontally extending slabl of refractory material toward a point of conuence beneath said slab, inguiding the flow outward and downward in a forking fashion from about the. center of its point of confluence, and

after nvergently toward a line of' `spaced from one another, around which molten glass streams successively flow before they are drawn into sheet form. 8 2H. In an apparatus for producing sheet glass` a plurality of directing members, positioned one above another, around which molten glass streams successively flow before they are drawn into sheet form. l

29. In an apparatus for producing sheet glass, a plurality of directing members, around which molten glass streams-successively flow before they are drawn into united sheet form, one of the members being formed of a heat resisting metal.

30. In an apparatus for producing sheet glass, a plurality of directing members, around which molten glass streams successively flow before they are drawn into united sheet form, one ot' vthe members being formed of a heat resisting metallic alloy.

31. In an apparatus for producing sheet glass, a plurality of direct-ing; members, around which the molten glass successively flows before it is drawn into sheet form, one of the members being formed of an alloy of nickel and tungsten.

32. In an apparatus for producing sheet glass, a pair of directing members, positioned l one above another, around which molten glass streams successively iow before they are drawn into united sheet form, the lower member being formed of a heat resisting metal. 1

33. In an apparatus for producing sheet. glass, a pair of directing members, positioned one above another, around which molten glass streams succesively flow before they are drawn into united sheet form, the. lower member being formed of a heat resisting metallic alloy.

34. In an apparatus for producing sheet glass, a pair of directing members, positioned one above another, around which the molten glass successively iiows before it is drawn l into sheet form, the lower member being formed of ari alloy of nickel and tungsten.Y

35. In anA apparatus for producing slieetf1 glass, a pair of directing' members, spacedone above the other, around which the molten glass successively flows before being drawn from the lower member in sheet form, the lower member having an uppe; edge l tor` splitting the molten v- .V-

from the upper member, and a lowervv edge where the glass streams Howing around the vmember reunite t'o form the sheet.

36. In an apparatus for producing sheet glass, a pair of directing members, spaced one above the other, around which molten glass streams successively How before being drawn from the lower member in united sheet form, the lower member having an upper edge for splitting the molten stream received from thev upper member, and a loweredge where the glass streams Howing aroundthe member reunite to form the sheet, the side walls ofthe .lower member, down which the molten glass Hows, first diverging outwardly from the upper edge, and then converging inwardly' to the lower edge,

37. In an apparatus for producing sheet glass, a pair of directing members, spaced one above the other, around .which molten A glass streams successively How before being drawn from the-lower member 'insunited sheet form, thevqlower member lhaving an upper edge forsplitting the ymolten stream received from the rupper member, and a lower edge where-the glass streams Howing around the member reunite to form the sheet,

the side walls of the lower member, down` which the molten lass Hows, first diver ing outwardly at a re ativel small angle om tho uppery edge, and tien converging in-l wardly at av sharper angleto the lower edge.

38. In an apparatus for producing sheet glass, a plurality of ,directing members, spaced one above another, around which the molten glass Hows before being drawn down .in sheet form from the lowermost member,

the glass unitingaetween said directing iembers 39. In an apparatus for producing sheet glass, a plurality of directing members,

spaced one above another, L,around which the molten glass Howsbefore/being drawn down in sheet form from the lowermost' member,"

`molten glass Hows before being drawn down in sheet form from 'the lowermost member,

means from which molten glass Hows in a sin le stream onto the uppermost lmember, an means for controlling the temperature of the molten glass as it Hows around the members, the said streams uniting between the directing members.`

441'. In an apparatus for producing sheet glass, a pair of directing members, positioned one above another, around which the molten glass successively Hows before it is drawn away in sheet form, the said streams uniting between the directing members, and

Signed at Toledo, in the county of Lucas and State of Ohio, this 22nd day `of February, 1924.

ENOCH T. FERNGREN.

,Ameans for adjusting the two members with y 

